The present paper investigates the energy savings associated with the implementation of retrofitting measures on Irish residential buildings. A detached residential dwelling, representative of approximately 40% of the residential stock in Ireland, was selected as experimental test bed. The building was progressively retrofitted to an all-electric dwelling. Retrofit measures included the installation of a photovoltaic array, a geothermal heat pump, an electric vehicle charging point, along with building fabric upgrades. The building was equipped with a home area network with more than 30 sensors with 15 min monitoring resolution. The experimental data collected during the experimental campaign aided the comprehensive calibration of an EnergyPlus model. This model was used to investigate the effectiveness of the implemented retrofit measures in terms of energy savings and CO2 reductions. Real-time data from the Irish power system operator was used to calculate the building carbon footprint for different levels of renewable energy penetration to the national grid. Results show that the all-electric retrofitted building can achieve energy savings of up to 45%, with CO2 reductions of approximately 29%, compared to the pre-retrofitted building. Implementing the retrofit measures at scale could potentially lead to carbon emission reductions up to 14% for rural areas in Ireland.